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    <!-- 求出1-1/2 + 1/3 - 1/4 + 1/5....... 1/100的和 -->
    <script>
        // 定义一个sum接收要求的数的和
        var sum = 0;
        // 先把1-100找出
        for(var i =1;i<=100;i++){
            // 根据奇偶判断是相加还是相减  偶数减   奇数加
            if(i%2===0){
                sum=sum-1/i;
            }else if(i%2 !==0){
                sum=sum+1/i
            }
        }
        console.log(sum);
        
    </script>
</body>
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